ultrasonic.h

00001 #ifndef MBED_ULTRASONIC_H
00002 #define MBED_ULTRASONIC_H
00003 
00004 #include "mbed.h"
00005 
00006 /** ultrasonic class.
00007  *  Used for HC-SR04 ultrasonic range sensor
00008  *
00009  * Example:
00010  * @code
00011  * #include "mbed.h"
00012  * #include "ultrasonic.h"
00013  *
00014  * ultrasonic usensor(PA_6, PA_7, 0.1, 0.25, &dist);
00015  *
00016  * int main() {
00017  *  //start mesuring the distance
00018  *  usensor.startUpdates();
00019  *  while(1){
00020  *      usensor.checkDistance();
00021  *   }
00022  * }
00023  * @endcode
00024  */
00025 class ultrasonic
00026 {
00027 public:
00028     /**iniates the class with the specified trigger pin, echo pin, update speed and timeout
00029      * @param trigPin The "trigger" pin for the ultrasonic sensor.  This is DigitalOut.
00030      * @param echoPin The "echo" pin for the ultrasonic sensor.  This is InterruptIn.
00031      * @param updateSpeed How often the ultrasonic sensor pings and listens for a response.
00032      * @param timeout How long to wait before giving up on listening for a ping.
00033      **/
00034     ultrasonic(PinName trigPin, PinName echoPin, float updateSpeed, float timeout);
00035     /**iniates the class with the specified trigger pin, echo pin, update speed, timeout and method to call when the distance changes
00036      * @param trigPin The "trigger" pin for the ultrasonic sensor.  This is DigitalOut.
00037      * @param echoPin The "echo" pin for the ultrasonic sensor.  This is InterruptIn.
00038      * @param updateSpeed How often the ultrasonic sensor pings and listens for a response.
00039      * @param timeout How long to wait before giving up on listening for a ping.
00040      * @param onUpdate(int) The function to be called when the distance is detected to have changed.
00041      **/
00042     ultrasonic(PinName trigPin, PinName echoPin, float updateSpeed, float timeout, void onUpdate(int));
00043     /** returns the last measured distance**/
00044     int getCurrentDistance(void);
00045     /** auses measuring the distance**/
00046     void pauseUpdates(void);
00047     /** tarts mesuring the distance**/
00048     void startUpdates(void);
00049     /**attachs the method to be called when the distances changes
00050      * @param method(int) The function to be called when the distance is detected to have changed.
00051      */
00052     void attachOnUpdate(void method(int));
00053     /**
00054     * Method:
00055     * changes the speed at which updates are made
00056     * @param updateSpeed how often to update the ultrasonic sensor
00057     **/
00058     void changeUpdateSpeed(float updateSpeed);
00059     /**gets whether the distance has been changed since the last call of isUpdated() or checkDistance()**/
00060     int isUpdated(void);
00061     /**gets the speed at which updates are made**/
00062     float getUpdateSpeed(void);
00063     /**call this as often as possible in your code, eg. at the end of a while(1) loop,
00064     and it will check whether the method you have attached needs to be called**/
00065     void checkDistance(void);
00066 private:
00067     DigitalOut _trig;
00068     InterruptIn _echo;
00069     Timer _t;
00070     Timeout _tout;
00071     int _distance;
00072     float _updateSpeed;
00073     int start;
00074     int end;
00075     volatile int done;
00076     void (*_onUpdateMethod)(int);
00077     void _startT(void);
00078     void _updateDist(void);
00079     void _startTrig(void);
00080     float _timeout;
00081     int d;
00082 };
00083 #endif